Over the last two years I've had the front end thoroughly examined at several different garages specializing in tires, suspension, etc. They've not been able to find anything. Again, it generally only happens in very warm weather and after I've been on the road for at least 30 minutes-- a soft clunking noise when I brake or accelerate; at times I sense I can feel it in the pedals. Very noticeable in stop and go traffic.